Understatement is the deliberate description of something in a way that makes it seem less important than it actually is. Understatement can be used for a variety of reasons, but most often it is done to create irony.
Understatement is the opposite of hyperbole, which is deliberate exaggeration.
1. In the middle of an intense thunderstorm: "We're having a little rain."
2. After wrecking your car: "There's a little scratch."
3. After coming home to find that your dog has torn apart couch cushions and strewn stuffing all over the floor: "Well, you had a little fun while I was gone."
4. Telling a friend about the expensive trip you just took to Disney World: "It's a little pricy."
5. When you have lost a thousand dollars in a poker game: "I lost a couple of dollars."
Examples of Understatement in Literature and Speech
1. "I have to have this operation. It isn't very serious. I have this little tumor on the brain." The Cather in the Rye
2. Talking of the shooting of Tom Robinson: "Seventeen holds in him. They didn't have to shoot him that much." To Kill a Mockingbird
3. On describing the discovery of DNA: "This structure has novel features which are of considerable biological interest." Watson and Crick
4. Mercutio in Romeo and Juliet describes his death wound as "a scratch, a scratch."